i2c: add nexell driver

Changes in relation to FriendlyARM's U-Boot nanopi2-v2016.01:
- i2c/nx_i2c.c: Some adaptions mainly because of changes in
  "struct udevice".
- several Bugfixes in nx_i2c.c.
- the driver has been for s5p6818 only. Code extended appropriately
  in order s5p4418 is also working.
- "probe_chip" added.
- pinctrl-driver/dt is used instead of configuring the i2c I/O-pins
  in the i2c-driver.
- '#ifdef CONFIG...' changed to 'if (IS_ENABLED(CONFIG...))' where
  possible (and similar).
- livetree API (dev_read_...) is used instead of fdt one (fdt...).

Signed-off-by: Stefan Bosch <stefan_b@posteo.net>

1 files changed, 28 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/i2c/nx_i2c.txt b/doc/device-tree-bindings/i2c/nx_i2c.txt
new file mode 100644
index 0000000..9f3abe7
--- /dev/null
+++ b/doc/device-tree-bindings/i2c/nx_i2c.txt
@@ -0,0 +1,28 @@
+I2C controller embedded in Nexell's/Samsung's SoC S5P4418 and S5P6818
+
+Driver:
+- drivers/i2c/nx_i2c.c
+
+Required properties:
+- #address-cells = <1>;
+- #size-cells = <0>;
+- compatible = "nexell,s5pxx18-i2c";
+- reg = <i2c_base 0x100>;
+        Where i2c_base has to be the base address of the i2c-register set.
+        I2C0: 0xc00a4000
+        I2C1: 0xc00a5000
+        I2C2: 0xc00a6000
+
+Optional properties:
+- clock-frequency: Desired I2C bus frequency in Hz, default value is 100000.
+- i2c-sda-delay-ns (S5P6818 only): SDA delay in ns, default value is 0.
+- Child nodes conforming to i2c bus binding.
+
+Example:
+	i2c0:i2c@c00a4000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "nexell,s5pxx18-i2c";
+		reg = <0xc00a4000 0x100>;
+		clock-frequency = <400000>;
+	};